The oil and gas exploration and extraction industry make wide use of coiled tubing, in for example well intervention and coiled tubing drilling. Coiled tubing is spoolable and thus may be deployed far more rapidly than conventional jointed drill pipe. Furthermore, coiled tubing will withstand a degree of axial compression, and is thus suitable for use in horizontal wells, where other reelable supports, such as wireline, cannot be used. In order to inject coil tubing into a well, and also to pull the tubing from the well, a tubing injector must be provided on surface. Conventional tubing injectors are generally very large and heavy, and also relatively complex. The main reason for this is the very large pulling and injection forces required for the successful deployment of coiled tubing.
In the offshore section of the industry there is a requirement to inject tubing into surface and subset pipelines, down leg structures, and in some cases downhole. However, the restricted space and access available offshore often prevents the use of larger conventional injection systems, and thus places limits on the available applications for coiled tubing.
It is among the objectives of embodiments of the present invention to provide an alternative method of injecting pipe, and preferred embodiments of the invention can be constructed in a very compact package.